Mpox: evidence for strengthening and sustaining global surveillance
Authors: Helen Callaby, N Claire Gordon
Journal: The Lancet Global Health (2023)

Public health bodies watched with alarm as the 2022 outbreak of mpox (formerly known as monkeypox) spread across countries, with COVID-19 still fresh in minds and concern that globally we are entering unpredictable times for infectious diseases. As we leave behind the golden age of antimicrobials and encounter an increasing number of infections outside their expected epidemiological and geographical niches, the establishment of robust, international surveillance systems and data sharing processes becomes of paramount importance. Yet again we are reminded that pathogens do not adhere to geographical borders. The outbreak, initially recognised in the UK,1WHOMonkeypox - United Kingdom of Great Britain and Northern Ireland.https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON383Date: May 18, 2022Date accessed: May 5, 2023Google Scholar has now reached 111 countries, with 87 301 confirmed cases and 130 deaths documented to date2WHO2022–23 Mpox (monkeypox) outbreak: global trends.https://worldhealthorg.shinyapps.io/mpx_global/Date: May 16, 2022Date accessed: May 3, 2023Google Scholar and, as the largest mpox outbreak reported to date, was a Public Health Emergency of International Concern until May 11, 2023. In The Lancet Global Health, Henry Laurenson-Schafer and colleagues3Laurenson-Schafer H Sklenovská N Hoxha A et al.Description of the first global outbreak of mpox: an analysis of global surveillance data.Lancet Glob Health. 2023; 11: e1012-e1023Summary Full Text Full Text PDF Google Scholar describe the global epidemiology of the 2022 outbreak via systematic reporting by WHO member states, providing both a global description of the outbreak and insights into the use of WHO surveillance and reporting systems. This study is the first global description of the 2022 mpox outbreak and confirms the observations of individual national and regional studies. Laurenson-Schafer and colleagues provide clear evidence of sustained, multi-country transmission of mpox. This finding is contrary to our previous understanding of the disease whereby transmission was thought to be primarily zoonotic with only short onward human to human transmission chains. By enabling comparison of country level data with the global picture, standardised reporting on this scale allows international consensus on the risk factors and groups most at risk in order to prioritise public health interventions. In the UK, for example, the very earliest cases included a case of perinatally acquired mpox virus infection within a family cluster,4Ramnarayan P Mitting R Whittaker E et al.Neonatal monkeypox virus infection.N Engl J Med. 2022; 387: 1618-1620Crossref PubMed Scopus (20) Google Scholar raising the possibility of a very widespread outbreak and also presenting conundrums for patients attending health-care services with more common exanthems such as those caused by the varicella zoster virus, because the high-level infection control and specimen handling precautions needed until a negative mpox result was returned caused substantial personal and organisational effects. However, the authors report an overall proportion of 1·1% of cases occurring in children younger than 18 years, and a similarly low rate of infection in women, allaying these initial concerns and allowing more appropriate management of patients at low risk. The UK epidemiology also challenged the epidemiological case definitions required for initial surveillance efforts.5Callaby H Wakerley D Houlihan C Gordon C Rampling T The monkeypox case definition in the UK is broad.Lancet. 2022; 4001301Summary Full Text Full Text PDF Scopus (0) Google Scholar While the UK remains vigilant, the global picture now confirms intimate contact as the most important method of transmission for this outbreak, with complex sexual networks, predominantly amongst men who have sex with men, a major contributing factor for sustaining mpox in non-endemic countries, and the data therefore support the targeted approaches of vaccination and public health campaigns. Health-care exposure was also initially a substantial concern, with health-care systems needing to provide urgent care to a large number of patients with a high consequence infection in an eery echo of the early days of COVID-19. This study confirms however, that health-care exposure has a minor role in overall transmission. In the UK, to date, there have been no health-care associated infections reported in the 2022–23 outbreak, contrary to previous concerns.6Adler H Gould S Hine P et al.Clinical features and management of human monkeypox: a retrospective observational study in the UK.Lancet Infect Dis. 2022; 22: 1153-1162Summary Full Text Full Text PDF PubMed Google Scholar Although sequencing data globally is somewhat scarce, the study also confirms the differing epidemiology between the two main lineages (clade I, formerly known as the Congo Basin or central African clade; and clade II, formerly known as the west African clade). From the genomic and epidemiological data, clade I continues to behave as we have expected mpox outbreaks to do so, with a zoonotic origin, minimal sexual transmission, and an increased proportion of cases in children, and clade II, particularly the B1 lineage, was responsible for the 2022 outbreak. How accurately the data reflect total global case numbers cannot, at this point, be determined. As might be expected, it is probable that countries with more limited health-care provision, and particularly those with limited laboratory resources, are underrepresented in these numbers. However, even with this caveat, there is now globally relevant evidence to support several of WHO's recommended key areas for actions to contain the spread of mpox, including sustaining and strengthening surveillance. As for COVID-19, international support for a collective, cohesive approach is of paramount importance. We declare no competing interests. Description of the first global outbreak of mpox: an analysis of global surveillance dataContinued global surveillance allowed WHO to monitor the epidemic, identify risk factors, and inform the public health response. The outbreak can be attributed to clade IIb MPXV spread by newly described modes of transmission. Full-Text PDF Open Access